1. Field of the Invention
This invention relates in general to removing a semiconductor chip from an existing package, and, more particularly, to a hot shear method and apparatus for removing a semiconductor chip from a defective controlled collapsed semiconductor chip connection (C4) package for low yield analysis.
2. Description of the Related Art
Before a new semiconductor device can be released into a market place, it is imperative that the product has undergone extensive testing. During such testing, it is not uncommon for the tested device to fail. Although, the manufacturer may have induced the failure to establish the active device parameters, more often than not, the reason for the failure is unknown. These types of failures can be related to the assembly process or to the device itself. Consequently, a low yield analysis of the failed device package must be conducted to help ascertain a solution.
FIGS. 1 and 2 illustrate a perspective and a cross-sectional view of a conventional device package 3, e.g., controlled collapsed semiconductor chip connection (C4), having a semiconductor chip 5 bonded and sealed to an organic substrate 7. Typically, the semiconductor chip 5 is bonded and sealed by an epoxy material 9 to the organic substrate 7, such as a BT laminate, a FR-4, or a cyanate ester substrate. The epoxy material 9 provides material properties to accommodate the dissimilar material properties between the silicon semiconductor chip 5 and the substrate 7. Additionally, the epoxy material 9 also acts as a filler between solder ball contacts 11 that allow I/O signals to move to/from the silicon semiconductor chip 5 and the organic substrate 7. The package 3 can be structurally defined by width W.sub.o, height H.sub.o, and length L.sub.o for the substrate 7, and by width W.sub.c, height H.sub.c, and length L.sub.c for the semiconductor chip 5 and the epoxy 9.
To conduct a low yield analysis of a failed C4 package 3, the silicon semiconductor chip 5 should be separated from the package 3 to accurately analyze and deduce the location and cause of the failure. For the low yield analysis to be effective, it is imperative for the separation process to limit any additional damage to the semiconductor chip 5 and/or the substrate 7 during the process.
A conventional technique used to remove a silicon semiconductor chip from a C4 package involves several steps. In general, the device is positioned into a jig or fixture, and the entire assembly is placed into an oven. Once the assembly has reached a desired temperature, it is removed from the oven and a shearing tool is used to remove the silicon semiconductor chip 5 from the organic substrate 7.
Although this technique may be effective in removing the silicon semiconductor chip 5 from the C4 package 3, it is not an effective and efficient method for the subsequent low yield analysis. This is true because of a lack of temperature stability, and thus repeatability, in the process. With this method, once the heated structure of the conventional method is removed for shearing, unavoidable temperature fluctuations make it difficult to separate the semiconductor chip 5 from the organic substrate 7 without further damaging either component of the package 3.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.